9. Input Devices¶
This week we had to:
- Probe an input device’s analog levels and digital signals
Gyumri lab¶
This week, under the guidance of Onik Babajanyan, we used an oscilloscope to measure analog and digital signals from input devices connected to our PCB.
Experiment 1: Potentiometer (Analog Pin)¶
We applied voltage to the analog pin of a potentiometer. As we rotated it, the waveform on the screen rose and fell smoothly in proportion to the movement — a continuous, gradual change.
Experiment 2: Photoresistor (Digital Pin)¶
We connected the oscilloscope to the digital pin of a photoresistor. Switching the light on and off produced sharp, immediate transitions on the screen — the signal jumping between high and low with no in-between.
Experiment 3: Photoresistor (Analog Pin)¶
We repeated the light test using the analog pin instead. This time the transitions were smooth, similar to what we observed with the potentiometer.
Conclusion¶
Analog signals change continuously, reflecting gradual shifts in input. Digital signals switch abruptly between two discrete states. Seeing both behaviors on the oscilloscope made the difference between them concrete rather than just theoretical.